This paper addresses the question of 'What is technology?' in order to develop a framework for the assessment and regulation of technology. I suggest that technology is how we build our world, drawing on the distinctions between the world and the earth, and between the human activities of labour, work and action, made by Hannah Arendt. Arendt's thought has a number of implications for how we should think about and assess the world, and thus technology: the world should not be judged instrumentally, but in terms of whether it provides a place for human action. A model of a possible framework for technology assessment is provided by the UK planning system.